In vitro characterization of MOD-5014, a novel long-acting carboxy-terminal peptide (CTP)-modified activated FVII.

INTRODUCTION: Recombinant FVIIa (rFVIIa) is an effective treatment for haemophilia through frequent administration. However, the short half-life of rFVIIa decreases its prophylactic ability to reduce bleeding. Carboxy-terminal peptide (CTP)-modified FVIIa (MOD-5014) is a long-acting rFVIIa developed for on-demand treatment of haemophilia using either an intravenous or subcutaneous injection with the aim of less frequent administrations, as well as for prophylactic use. AIM: The comprehensive evaluation of the activity MOD-5014 vs commercially available rhFVIIa, as well as their interaction with cofactors and inhibitors. METHODS: The in vitro characterization included clotting activity, affinity by surface plasmon resonance, cleavage of synthetic substrates, thrombin generation (TG) and rotation thromboelastometry. RESULTS: Reduced specific activity was obtained for MOD-5014 compared to rhFVIIa, while both compounds demonstrated comparable affinity to tissue factor (TF). MOD-5014 showed reduced TG when spiked at a similar concentration as rhFVIIa, suggesting that an increased concentration might be needed in a clinical setting to provide initial haemostatic effect. MOD-5014 demonstrated a slightly lower affinity for binding to activated platelets and slightly lower proteolytic activity on the platelet surface, possibly as the fusion of CTP has the potential to sterically hinder binding to both the platelet membrane and to protein substrates. Both compounds showed a similar dose-dependent stimulatory effect on clot formation, and both showed a similar deactivation pattern following incubation with TF pathway inhibitor (TFPI), antithrombin and heparin. CONCLUSION: The comparable in vitro activity of MOD-5014 and rhFVIIa paves the way for in vivo pharmacology evaluations of MOD-5014 in preparation for clinical studies.

Vaccinations are not associated with inhibitor development in boys with severe haemophilia A.

BACKGROUND: Inhibitor development in previously untreated patients (PUPs) with severe haemophilia A is a multifactorial event. It is unknown whether paediatric vaccinations given in close proximity to factor VIII (FVIII) are associated with inhibitor development. OBJECTIVE: To assess whether paediatric vaccinations in close proximity to FVIII within the first 75 exposure days (EDs) are associated with inhibitor development in PUPs with severe haemophilia A. METHODS: We included 375 PUPs with severe haemophilia A (<0.01 IU/mL) from the PedNet Registry who had received vaccinations between the first and 75th ED or inhibitor development. Inhibitor risk was compared between patients who did and who did not receive vaccinations within 24, 72 or 120 hours of FVIII infusion. Unadjusted and adjusted hazard ratios were calculated for any or repeated vaccinations in close proximity to FVIII, using Cox regression. RESULTS: Inhibitor development occurred in 77 of 375 patients (20.5%). Overall inhibitor development appeared similar or lower in patients receiving vaccinations in close proximity to FVIII as compared to patients receiving vaccinations without FVIII: for 24 hours, this was 19.2% and 21.4% (P = .186), for 72 hours, 16.4% and 27.3% (P = .023) and for 120 hours, 18.3% and 25.0% (P = .085), respectively. CONCLUSION: We found no association between vaccinations given in close proximity to FVIII exposure within the first 75 EDs and inhibitor development. Our data do not support avoiding administration of FVIII at time of routine vaccinations.

Estimating the potential cost of a high dose immune tolerance induction (ITI) therapy relative to the cost of a combined therapy of a low dose ITI therapy with bypassing agent prophylaxis.

INTRODUCTION: The International Immune Tolerance Study (I-ITI) demonstrated comparable success rates between low (FVIII 50 IU/kg/TIW) and high dose (FVIII 200 IU/kg/day) regimens. While costlier, the high dose ITI regimen achieved shorter time-to-treatment success with fewer bleeding episodes compared to the low dose ITI regimen. Adding bypassing agent prophylaxis (BAP) to a low dose ITI regimen may reduce bleeding while still being less costly than high dose ITI. AIM AND METHODS: An economic model was developed to compare high dose ITI to low dose ITI with BAP. All model inputs were derived from clinical trials. The I-ITI study indicated a median time to negative inhibitor titre of 4.6 and 9.2 months and average number of bleeds/patient of 4.2 and 9.9 for the high and low dose regimens respectively. Based on the BAP trials, aPCC (85 U/kg/TIW) and rFVIIa (90 µg/kg/day) achieved a 62% and 45% reduction in bleeding frequency respectively. Cost analysis was from a US third party payer perspective and limited to drug costs. One-way, two-way and probabilistic sensitivity analyses were performed. RESULTS: Costs of low dose ITI with aPCC prophylaxis until negative inhibitor titre is achieved was 24.0% less compared to high dose ITI. Low dose ITI with rFVIIa prophylaxis cost 46.5% more compared to high dose ITI. Model results were robust in the majority of the sensitivity analyses. CONCLUSION: A low dose ITI regimen with aPCC prophylaxis may be cost saving compared to a high dose ITI regimen with the potential to reduce morbidity by lowering the risk for breakthrough bleeds.

Activity of Von Willebrand factor and levels of VWF-cleaving protease (ADAMTS13) in preterm and full term neonates.

Von Willebrand Factor (VWF) has a central role in primary hemostasis. Its biological activity is related to the size of VWF multimers, spontaneously binding to platelets and inducing circulating microthrombi formation. This process is down-regulated by the VWF cleaving protease ADAMTS13 (A Disintegrin and Metalloprotease with ThromboSpondin motif). To date, information regarding the levels of ADAMTS13 in neonates and preterm infants is scarce. Our aim was to study ADAMTS13, VWF antigen (Ag) and Ristocetin cofactor (RiCof) activity in neonates and evaluate potential correlations with perinatal complications. Our cohort consisted of 128 (48/128: born preterm) neonates, born in Sheba Medical Center and followed until hospital discharge. Control group consisted of 20 healthy adults. As expected, a significant elevation of VWF:Ag was observed in preterm and term infants compared to adults. VWF:Ag levels were highest in full term infants (Median 129.0 IQR 33.8) and lowest in adults (Median 119.0 IQR 58.5) (p<0.05), and RiCoF levels in neonates were higher than in adults. ADAMTS13 was significantly (p<0.05) higher in preterm babies in comparison to full term and adult controls. Neonates that underwent stressful conditions or experienced vascular complications such as IUGR, ROP, NEC, had lower levels of ADAMTS13 in our study. Further studies are required to validate and asses potential significance of these findings.

Primary prophylaxis for children with severe congenital factor VII deficiency - Clinical and laboratory assessment.

Severe congenital factor VII (FVII) deficiency is a rare bleeding disorder. Prophylaxis with replacement therapy has been suggested to patients, yet the most beneficial dosing regimens and therapy intervals are still to be defined. Due to the lack of evidence-based data, we hereby present our experience with long-term administration and monitoring primary prophylaxis in children with severe FVII deficiency and an extremely high bleeding risk. Four children with familial FVII deficiency, treated by prophylactic recombinant activated factor VII (rFVIIa), 15-30µg/kg/dose, given 2-3 times weekly since infancy, are discussed. Clinical follow up and monitoring laboratory assays, including thrombin generation, measured at various time points after prophylactic rFVIIa administration are presented. Among our treated patients neither FVII activity nor thrombin generation parameters (both already declined 24h post rFVIIa administration) were able to predict the impact of prophylaxis, and could not be used as surrogate markers in order to assess the most beneficial treatment frequency. However, the long clinical follow-up and comprehensive laboratory assessment performed, have shown that early primary prophylaxis as administered in our cohort was safe and effective.

Women with congenital factor VII deficiency: clinical phenotype and treatment options from two international studies.

INTRODUCTION: A paucity of data exists on the incidence, diagnosis and treatment of bleeding in women with inherited factor VII (FVII) deficiency. AIM: Here we report results of a comprehensive analysis from two international registries of patients with inherited FVII deficiency, depicting the clinical picture of this disorder in women and describing any gender-related differences. METHODS: A comprehensive analysis of two fully compatible, international registries of patients with inherited FVII deficiency (International Registry of Factor VII deficiency, IRF7; Seven Treatment Evaluation Registry, STER) was performed. RESULTS: In our cohort (N = 449; 215 male, 234 female), the higher prevalence of mucocutaneous bleeds in females strongly predicted ensuing gynaecological bleeding (hazard ratio = 12.8, 95% CI 1.68-97.6, P = 0.014). Menorrhagia was the most prevalent type of bleeding (46.4% of patients), and was the presentation symptom in 12% of cases. Replacement therapies administered were also analysed. For surgical procedures (n = 50), a receiver operator characteristic analysis showed that the minimal first dose of rFVIIa to avoid postsurgical bleeding during the first 24 hours was 22 µg kg(-1) , and no less than two administrations. Prophylaxis was reported in 25 women with excellent or effective outcomes when performed with a total weekly rFVIIa dose of 90 µg kg(-1) (divided as three doses). CONCLUSION: Women with FVII deficiency have a bleeding disorder mainly characterized by mucocutaneous bleeds, which predicts an increased risk of ensuing gynaecological bleeding. Systematic replacement therapy or long-term prophylaxis with rFVIIa may reduce the impact of menorrhagia on the reproductive system, iron loss and may avoid unnecessary hysterectomies.

Achievements, challenges and unmet needs for haemophilia patients with inhibitors: Report from a symposium in Paris, France on 20 November 2014.

Over the past 20 years, there have been many advances in haemophilia treatment that have allowed patients to take greater control of their disease. However, the development of factor VIII (FVIII) inhibitors is the greatest complication of the disease and a challenge in the treatment of haemophilia making management of bleeding episodes difficult and surgical procedures very challenging. A meeting to discuss the unmet needs of haemophilia patients with inhibitors was held in Paris on 20 November 2014. Topics discussed were genetic and non-genetic risk factors for the development of inhibitors, immunological aspects of inhibitor development, FVIII products and inhibitor development, generation and functional properties of engineered antigen-specific T regulatory cells, suppression of immune responses to FVIII, prophylaxis in haemophilia patients with inhibitors, epitope mapping of FVIII inhibitors, current controversies in immune tolerance induction therapy, surgery in haemophilia patients with inhibitors and future perspectives for the treatment of haemophilia patients with inhibitors. A summary of the key points discussed is presented in this paper.

BAY 81-8973 safety and efficacy for prophylaxis and treatment of bleeds in previously treated children with severe haemophilia A: results of the LEOPOLD Kids Trial.

INTRODUCTION: BAY 81-8973, a full-length, unmodified, recombinant factor VIII (FVIII) in development for treatment of haemophilia A, has the same primary amino acid sequence as Bayer's sucrose-formulated recombinant FVIII but is produced with more advanced manufacturing technologies. AIM: To demonstrate safety and efficacy of BAY 81-8973 for prophylaxis and treatment of bleeds in previously treated children. METHODS: In this phase III, multicentre, open-label, nonrandomized study, boys aged ≤12 years with severe haemophilia A and ≥50 exposure days (EDs) to FVIII products received prophylaxis with BAY 81-8973 25-50 IU kg(-1) ≥2 times weekly for ≥50 EDs. The efficacy endpoint was annualized number of total bleeds. Adverse events (AEs) and immunogenicity were assessed. RESULTS: Fifty-one patients were treated (age: <6 years, n = 25; 6-<12 years, n = 26) with a 2× per week (43%) or >2× per week (57%) regimen at study start. Median [quartile 1; quartile 3 (Q1; Q3)] annualized number of bleeds for the combined age groups was 1.90 (0; 6.02) for total bleeds, 0 (0; 2.01) for joint bleeds and 0 (0; 0) for spontaneous bleeds. Median (Q1; Q3) annualized number of total bleeds within 48 h of previous prophylaxis infusion was 1.88 (0; 3.97) for children aged <6 years and 0 (0; 1.96) for children aged 6-<12 years. No drug-related serious AEs or inhibitors were reported. CONCLUSIONS: Prophylaxis with BAY 81-8973 using individualized prophylaxis regimens of 2× per week, 3× per week and every-other-day infusions was efficacious in prevention and treatment of bleeds in children with severe haemophilia A. Treatment with BAY 81-8973 was well tolerated.

Central venous access device (CVAD) complications in Haemophilia with inhibitors undergoing immune tolerance induction: Lessons from the international immune tolerance study.

INTRODUCTION: Central venous access devices (CVADs) are frequently required as stable long-lasting venous access in children with haemophilia, especially those requiring immune tolerance induction (ITI) for inhibitors. CVAD infection is one of the most frequently reported catheter-related complications in this patient population. AIM: Detailed review of CVAD complications from the International ITI (I-ITI) study and analysis of potential risk factors for such complications. METHODS: Retrospective analysis of prospectively obtained data from the I-ITI study primarily focused on CVAD-related complications. RESULTS: A total of 115 children were recruited and 183 CVADs were placed in 99 subjects resulting in 121,206 CVAD-days observed on-study. A total of 124 CVAD infections were reported in 41 of 99 (41%) subjects with an overall infection rate of 0.94 per 1000 CVAD-days (interquartile ranges 0-1.7). A similar number of infections were observed in the two treatment arms (median: 2 and 3 in high dose and low dose respectively). Infections occurred more frequently in the presence of external catheters than with fully implanted catheters (P = 0.026). Infected patients were significantly younger at the time of CVAD insertion (median age: 22 vs. 25 months, P = 0.020). Patients with Gram-positive infections were also significantly younger than those with Gram-negative infections (median age: 17 vs. 25 months, P < 0.0001). CONCLUSION: CVAD infection was the most common complication observed in children with severe haemophilia and inhibitors in the frame of the I-ITI study. Younger age at CVAD insertion and external CVAD were associated with higher risk for infection. ITI outcome was unaffected by CVAD infections.

Oral surgery-associated postoperative bleeding in haemophilia patients - a tertiary centre's two decade experience.

Our goal in this research was to evaluate potential and targeted therapy, correlated with haemophilia severity and dental procedural risk, to reduce postoperative bleeding risk. Patients with haemophilia who were treated at the Oral and Maxillofacial Surgery Clinic at Sheba Medical Center between 1996 and 2012 comprised the study cohort. Data collected included disease history and severity, perioperative factor concentrate therapy, local haemostatic agent application, systemic tranexamic acid use and outcome. Bleeding was defined as excessive bleeding during or within 20 days following procedure. Dental procedures (n = 1968) of 125 patients were studied. Patients' bleeding risk score was evaluated according to the severity of haemophilia with or without the presence of an inhibitor, presence of comorbid coagulopathy and the type of dental procedure. Thirty-four patients undergoing a total of 880 high-risk and 1088 low-risk procedures suffered 40 postoperative bleeding events that necessitated further dental and/or haematological intervention. Among risk factors for delayed bleeding, the use of fibrin glue was significantly (P = 0.027) associated with the risk of postprocedural bleed probably as it was applied to high-risk patients and procedures. Earlier treatment period (P = 0.055), postprocedure hospitalization (P = 0.039) and dental "high-risk" procedures (P < 0.0001) also increased bleeding risk. Patients with haemophilia may be safely treated if meticulous haemostasis is applied, along with fibrin glue and systemic therapy as required. Factor transfusions are not mandatory and should be applied considering the procedure-related risk and the patient's calculated haematological risk for bleeding.

Clinical and laboratory characteristics of paediatric and adolescent index cases with venous thromboembolism and antithrombin deficiency. An observational multicentre cohort study.

Venous thromboembolism [TE] is a multifactorial disease and antithrombin deficiency [ATD] constitutes a major risk factor. In the present study the prevalence of ATD and the clinical presentation at TE onset in a cohort of paediatric index cases are reported. In 319 unselected paediatric patients (0.1-18 years) from 313 families, recruited between July 1996 and December 2013, a comprehensive thrombophilia screening was performed along with recording of anamnestic data. 21 of 319 paediatric patients (6.6%), corresponding to 16 of 313 families (5.1%), were AT-deficient with confirmed underlying AT gene mutations. Mean age at first TE onset was 14 years (range 0.1 to 17). Thrombotic locations were renal veins (n=2), cerebral veins (n=5), deep veins (DVT) of the leg (n=9), DVT & pulmonary embolism (n=4) and pelvic veins (n=1). ATD co-occurred with the factor-V-Leiden mutation in one and the prothrombin G20210A mutation in two children. In 57.2% of patients a concomitant risk factor for TE was identified, whereas 42.8% of patients developed TE spontaneously. A second TE event within primarily healthy siblings occurred in three of 313 families and a third event among siblings was observed in one family. In an unselected cohort of paediatric patients with symptomatic TE, the prevalence of ATD adjusted for family status was 5.1%. Given its clinical implication for patients and family members, thrombophilia testing should be performed and the benefit of medical or educational interventions should be evaluated in this high risk population.

Antiphospholipid antibodies in neonates with stroke--a unique entity or variant of antiphospholipid syndrome?

OBJECTIVE: YB current affiliation: Department of Pediatrics, Hadassah-Hebrew University Medical Center, Mount Scopus, Israel YB and MJS contributed equally to the study and should be regarded as joint first authors on this manuscript. Antiphospholipid syndrome (APS) may present with thrombosis and persistently elevated titers of antiphospholipid antibodies (aPL) in the neonatal period. Our aim was to investigate the course and impact of elevated titers of aPL in a cohort of infants presenting with either perinatal arterial ischemic stroke (PAS) or cerebral sinus vein thrombosis (CSVT) during the perinatal period. STUDY DESIGN: Sixty-two infants with clinically and radiologically confirmed PAS or CSVT presenting in the neonatal period underwent thrombophilia workup that included Factor V Leiden (FVL), PII20210A mutation, MTHFR 677T polymorphism, protein C, protein S, aPL namely either circulating lupus anticoagulant (CLA), anticardiolipin antibodies (aCL) or anti-ß2-glycoprotein-1 (ß2GP1). Mothers also underwent thrombophilia workup. RESULTS: Twelve infants with persistently elevated aPL were prospectively followed. Infants with positive aPL showed no concordance with presence of maternal aPL. All children were followed for a median of 3.5 years (range: nine months to 19 years) with repeated aPL testing every three to six months. Anticoagulant therapy initiation and therapy duration varied at the physician's discretion. In 10/12 cases aPL decreased to normal range within 2.5 years; one female with complex thrombophilia risk factors required indefinite prolonged anticoagulation. None of the infants showed recurrent thrombosis or any other APS manifestations, despite lack of prolonged anticoagulation. CONCLUSIONS: The presence of aPL may be important in the pathogenesis of cerebral thrombosis in neonates. Nevertheless, the nature of thrombophilia interactions in this period and their therapeutic impact warrants further investigation.

Combined administration of FVIII and rFVIIa improves haemostasis in haemophilia A patients with high-responding inhibitors--a thrombin generation-guided pilot study.

Treatment of haemophilia A patients with inhibitors is challenging, and may require individually tailored regimens. Whereas low titre inhibitor patients may respond to high doses of factor VIII (FVIII), high-responding inhibitor patients render replacement therapy ineffective and often require application of bypassing agents. Thrombin generation (TG) assays may be used to monitor haemostasis and/or predict patients' response to bypass agents. In this study we defined by TG, the potential contribution of FVIII to recombinant activated factor VII (rFVIIa)-induced haemostasis in inhibitor plasma. Based upon results, prospectively designed individual regimens of coadministration of rFVIIa and FVIII were applied. Plasma samples from 14 haemophilia patients with inhibitors (including high titre inhibitors) were tested. The response to increasing concentrations of FVIII, rFVIIa or both was assayed by TG. Eight patients, chosen following consent and at physician's discretion, comprised the combined FVIII-rFVIIa therapy clinical study cohort. Combined spiking with FVIII/rFVIIa improved TG induced by rFVIIa alone in all inhibitor plasmas. Combined rFVIIa and FVIII therapy was applied during bleeding or immune tolerance to eight patients, for a total of 393 episodes. Following a single combined dose, 90% haemostasis was documented and neither thrombosis nor any complications evolved. During study period decline of inhibitor levels and bleeding frequency were noted. Pre-analytical studies enabled us to prospectively tailor individual therapy regimens. We confirmed for the first time that the in vitro advantage of combining FVIII and rFVIIa, indeed accounts for improved haemostasis and may safely be applied to inhibitor patients.

On-demand treatment of bleeds in haemophilia patients with inhibitors: strategies for securing and maintaining predictable efficacy with recombinant activated factor VII.

On-demand therapy with recombinant activated factor VII (rFVIIa) can provide effective haemostasis for spontaneous bleeds in haemophilia patients with inhibitors. However, treatment approaches vary amongst physicians, positively or negatively affecting outcomes. A panel of physicians proposed recommendations for securing and maintaining predictable efficacy with rFVIIa, comparing these with 'real-life' patient management, using a questionnaire circulated to other expert physicians from haemophilia care centres in Europe and the United States. For rFVIIa treatment of spontaneous bleeds in inhibitor patients, early intervention with the highest appropriate dose is recommended. Home-based therapy can facilitate early intervention. If additional rFVIIa therapy is required after the initial dose, rFVIIa 90 µg kg(-1) may be administered at 2-3 h intervals. Treatment should be tailored to bleed site/severity, recognizing the advantages of appropriate adjunct therapy. Questionnaire results suggested that many respondents adopted strategies in line with the recommendations. Most (36/46) recommended initial therapy within 1 h of bleed onset. rFVIIa 270 µg kg(-1) was the most frequently prescribed/recommended initial dose for paediatric (aged ≤ 15 years; 22/44 respondents) and adult (aged > 15 years; 23/44 respondents) patients. However, there may be opportunity for improved bleed management on occasion, with regard, for instance, to dosing and dose interval. To secure and maintain predictable efficacy with rFVIIa, judicious dose selection and treatment timing are important, together with adjunct therapy where necessary. As inhibitor patients present with different bleeding scenarios, a tailored treatment approach should be adopted.

Thrombocytopenia and bleeding in dental procedures of patients with Gaucher disease.

The risk of bleeding during dental procedures may be increased in patients with Gaucher disease. We aimed to evaluate potential coagulation and platelet function abnormalities and targeted therapy accordingly. Patients with type 1 Gaucher disease who were treated at the Oral and Maxilo-Facial surgery clinic at Sheba Medical Center between 2003 and 2010 comprised the study cohort. Data collected included disease history, enzyme treatment, platelet counts, dental therapy and outcome. Bleeding was defined as excessive bleeding during or immediately following procedure. Coagulation studies and platelet function tests including aggregometry were performed on all patients. Dental procedures (n = 14, including eight teeth extractions, two crown lengthening procedures, one cyst enucleation and three deep dental scaling) of seven patients were studied. Mean platelet count prior to procedure was 73 K ± 14.8 mm(3). Patients bleeding risk score was calculated according to previous history of bleeding tendency, degree of thrombocytopenia, presence of comorbid coagulopathy and the type of dental procedure. Two patients with highest risk score received prophylactic platelet transfusions, three patients (medium-risk) received DDAVP preprocedure and all received systemic tranexamic acid, which was the only systemic therapy for low-risk patients. Meticulous surgical local haemostasis was applied. No excessive intra-operative or postoperative bleeding occurred. Patients with Gaucher disease who have thrombocytopenia and abnormal platelet function tests may be safely treated if meticulous haemostasis is applied along with systemic therapy as required. Platelet transfusions are not mandatory and should be applied considering the procedure-related risk and the patient's calculated haematological risk for bleeding.